Acetic Acid Exposure of Front-Side Metallization Paste for n-TOPCon Solar Cells with Laser-Enhanced Contact Optimization (LECO) Process

Degradation due to acetic acid in photovoltaic (PV) modules has been commonly observed for both outdoor operations and accelerated aging tests like damp-heat (DH) exposure. As n-type TOPCon Solar cells with Laser-Enhanced Contact Optimization (LECO) process has become a mainstream photovoltaic cell technology, the reliability and durability of TOPCon-LECO solar cells has become essential. In this paper, the acetic acid exposure study of different metallization pastes for screen-printed industrial n-TOPCon-LECO solar cells are studied. Current-Voltage, electroluminescence, SEM-EDS measurements of the metal contacts before and after acetic acid treatments are characterized. The study confirms degradation mechanisms in acetic acid mainly comes from corrosion of metal contacts. The corrosion resistance of paste is affected by the composition of metallization pastes, including whether have Al additive and choice of glass frit. LECO glass frits with different lead amount ladder were investigated, and a TOPCon-LECO paste with good electrical performance and acetic acid resistance was developed.